SimScale CAE Forum

Need help in conversion of carbon monoxide into ppm


Hello All,

I have provided the source term of CO (with total value as 0.0010 kg/s) using passive scalar method. image

as kg/s in the simulation. in the same way as the above image, i have assigned different flux for different Cartesian boxes in the simulation domain. i am getting the scalar value as shown in the below legend.

will any one please suggest me how to convert the above legend into ppm levels.


Hi @rkaifi!

You can also calculate this using Paraview as suggested by our PowerUser @tcakir here: Pollution exhaust in a garage - let us know if you have any further questions.



Help needed to covert the passive scalar into ppm of the passive scalar

(Kg/s) * (1/T) *(1/density of air) * (1/volume of domain) *10^6 =PPM

(Kg/s) = co source term given with this units in the passive scalar box

T = Passive scalar quantity (1/s)

Density of air = kg/m^3

Volume of domain = m^3

please conform if the above approach is correct. @jousefm


Will you please tell me what is the unit of scalar T1 in the legend above. or please tell me what is the unit of scalar T1 in the link which you have given.

Pollution exhaust in a garage.

above is the link of your reference given to me.


use this image for better understanding.

thanks a lot for you time and consideration.


Hey @rkaifi!

Sorry for not getting back to you! I completely missed that. I think that doc entry can help you out (see note at the very bottom):